Semiconductor devices are provided for various applications including sensors, in particular relative humidity sensors. A humidity sensor must be in contact with the environment and can thus be subject to condensation. Many sensor applications require fast recovery from condensation. Water droplets that are present on the sensor region should instantaneously vanish when the temperature rises above the dew point, which is the temperature at which the water vapor in a sample of air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates.
US 2013/0069176 A1 discloses an integrated circuit package comprising a sensor element area covered with a protection layer. The integrated circuit is mounted on a carrier and connected by bond wires. An encapsulation covering the bond wires has an opening over the sensor element area. Inside the opening the protection layer comprises a channel surrounding the sensor element area.
JP 2010-050452 A discloses a method for manufacturing a sensor device with a plurality of chips arranged on a lead frame. A detector structure of the chips may comprise a polymer membrane of a humidity sensor. A buffer layer is formed above an integrated electronic circuit and leaves the detector structure free. A molded cover touches the buffer layer at the periphery of the detector structure, thus forming a sealed cavity above the detector structure.
JP 2012-068054 A discloses an electrostatic capacitance-type humidity sensor comprising a moisture-sensitive film surrounded by a hydrophilic film, which has a groove where condensed water forms a film. If the temperature of the air around the humidity sensor becomes higher than the dew-point temperature, the water in the groove part of the hydrophilic film evaporates, and dirt contained in the water remains.
US 2009/0243015 A1 discloses a method for manufacturing a semiconductor device wherein a resin layer is formed on an upper surface of a substrate including a photodiode such that the resin layer does not cover a light receiving region. Concentric grooves are formed in the resin layer so that the grooves surround the light receiving region. The photodiode is sealed with a molding resin. The grooves prevent molding resin from flowing into the light receiving region.
DE 112013004203 T5 discloses a sensor device comprising a moisture-sensitive layer, which is provided with a depression to prevent resin from entering a measurement portion during molding.
JP 2002-162380 A discloses a semiconductor ion sensor comprising a recessed portion around the ion sensing section. The recessed portion prevents inflow of resin into the ion sensing section.